Corona Treatment Automation
Corona treatment is a process that increases the surface energy of a plastic film using high voltage. After treatment, liquid chemicals wet the surface much more evenly than they would prior to the treatment. Inexpensive corona treatment can be done using a handheld device, as seen above, but this process does not produce consistent results, and because of the hight voltage it is dangerous.
By automating this process, I could treat these films much more consistently and quickly, and without the risk of electric shock. I wanted to put the device on an x-y axis and have it run a repeatable pattern on a sample every time.
I started by ripping apart an old flatbed scanner and using the built-in stepper motor to control a moving platform. This was my x-axis. I then assembled a frame from 80/20 profile about the flatbed and installed two rails with bearings. This would be m y-axis, controlled by another stepper motor, shown above. To mount the corona device itself, I had to design and 3D-print a "glove" that perfectly matched the device's external curves (also shown above). This part could have been made using a lathe, however I wanted to be able to mount it easily to the 80/20 bearing with side tabs.
Corona Treatment Component Design
These supports were designed to slide along the profile with very little friction. They were used in place of the bearings when the y-axis bearings started locking. Although the 80/20 aluminum profile is great for prototyping quickly, it is not straight enough to be a shaft, and the plastic sliding supports allowed for some deflection.
The corona device's holder just after printing. This was printed in a nylon/carbon fiber suspension material called onyx for its incredible strength.
One of these sliding supports place on the profile.
These are the first and second versions of the stepper motor mount. The first version (black) was not rigid enough to reduce vibration.
This stepper motor, responsible for the y-axis motion, was mounted to the 80/20 profile using this custom mount.